This application claims the priority of German patent document 199 21 313.5, filed Jul. 10, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a control device for the cooling and heating circuit of an internal combustion engine.
In order to control the cooling and heating circuit of an internal combustion engine, thermostats are known from practice which, as a function of temperature, connect a bypass circuit in the warm-up phase of the internal combustion engine. In addition, intermittently operated valves are known which, in the heating circuit, connect the cooling-medium flows in accordance with predefined requirements.
U.S. Pat. No. 4,644,909 discloses a cooling system for an internal combustion engine in which the control of the cooling medium flow is carried out by a valve having a rotary slide. The valve, having a radial inlet opening and a radial and an axial outlet opening, has a sleeve-like rotary slide which is driven by a stepping motor.
German patent document No. 44 16 039 describes a regulating valve which has a valve element constructed as a rotary slide. This very complicated shaped valve element is able to connect a number of inlet and outlet openings located in one radial plane to one another. As a result, it is possible for mixed states between a number of the inlet and outlet openings to be achieved.
The drawback with these valves is that not all adjustment or mixed positions are possible, so that in order to achieve specific mixtures and specific circuit connections, a number of valves are needed. Furthermore, the aforementioned valves are very large in terms of their overall space and are restricted in terms of their installation position by the necessary, predefined position of the inlet and outlet lines.
In German patent document No. 198 09 124, which is not considered prior art, a description is given of a control device for the cooling and heating circuit of an internal combustion engine in which a rotary slide is arranged in a valve housing. This substantially sleeve-like rotary slide can connect an axial collecting opening, for the supply or discharge of cooling medium, to an individual inlet or outlet opening, or alternatively, during the performance of a mixing operation, can make an overlapping connection between two adjacently located inlet or outlet openings.
Here too, for the most comprehensive functioning possible, one is bound by the predefined position of the collecting opening and the inlet or outlet openings. However, if this disadvantage is accepted with regard to the rigidly predefined installation position of the connections, then the aforementioned control device is capable of implementing a number of part-circuits in all the conceivable variants of mixing, bypass or sole operation of one of the part-circuits.
The present invention is based on the object of providing a control device in which a number of functions of setting and connecting elements are integrated in such a way that, if required, further regulating elements in a cooling and heating circuit of a motor vehicle can be dispensed with, and which moreover permits a large variability in the configuration of the position of the external connecting elements.
Using the control device according to the present invention, the entire circuit for cooling and for heating for virtually all the situations which arise in practice can be regulated with a single appliance. Both individual openings can be selected, and mixing operations are also possible, so that it is possible to dispense with further control and regulating elements in the cooling and heating circuit of the internal combustion engine.
By means of a preferred embodiment of the present invention, in addition to the individual flows, all the mixing stages which occur in practice can also be implemented. In addition, in the case of the control device according to the present invention, only low pressure losses occur, and high setting speeds may be implemented at the same time.
As a result of the simple and effective construction, in addition to low pressure losses, inexpensive mass production or high-volume production of the control devices according to the invention is also made possible.
In a further preferred embodiment of the present invention, the control device, or at least parts of the control device, are constructed as an integrated recess in a component of the internal combustion engine or of one of its additional units.
This means that, for example, the lower housing part with its associated connections can be integrated directly into the crankcase of the internal combustion engine or into a component of the delivery pump. As a result of the arbitrary position and outgoing route of the connecting stubs, and as a result of the use of feed channels integrated into the upper housing part and/or the lower housing part for the cooling medium, this form can be cast very simply into the crankcase or the like during the production of the latter. This valve housing, integrated or at least semi-integrated in this way, permits further advantages with regard to the overall space and the usual and required sealing of connecting lines to the connecting stubs, since these seals can be dispensed with entirely or at least in the integrated part of the valve housing.
Further advantages result with regard to the overall space requirements, the mounting options, the required mounting time, and the required outlay for mounting during the production of a motor vehicle with the control device according to the present invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.